The present embodiments relate to acoustic arrays for medical ultrasound. Acoustic arrays are formed from semiconductor or piezoelectric material. Piezoelectric materials include solid piezoelectric or composites. The materials transduce between acoustic and electrical energies.
The material is divided into elements, such as dicing a slab of piezoelectric material into a linear array of elements as shown in FIG. 2. By mounting on a rigid or semi-rigid backing, the array of elements maintains a desired planar emitting face. The arrangement of elements may be curved for a curved linear array. For example, an array formed from piezoelectric composite material is warped. The elements on the end are positioned away from an azimuth axis. The emitting face of the array is flat in elevation but curved along azimuth.
Two-dimensional arrays are used for three-dimensional imaging. Transducer material is divided into elements along two-dimensions. However, the number of elements becomes large. An alternative is to steer mechanically in one dimension, such as a one-dimensional array in a wobbler transducer. However, the mechanical steering requires space and adds complexity.
Acoustic arrays may be positioned in a catheter, endocavity probe, or other device for insertion into a patient. Due to the size of the catheter or probe, there may be limited space for conductors or mechanical structures. However, the ability to scan in three-dimensions from a catheter is desired, such as for ablation procedures. For example, U.S. Pat. No. 7,666,143 shows twisting a one-dimensional array in a catheter for volume imaging. As another example, U.S. Pat. No. 7,500,954 shows a multidimensional array that is hinged to expand for volume imaging. The hinge may use a memory metal for operation.
Other complex array geometries may be used. However, such arrays may require complex and expensive manufacturing techniques. Fixturing and components with machined parts that match the desired curvature may lead to high cost in materials, tooling, and labor. Twisting may place extra stress on the array, resulting in a greater failure rate in manufacturing and/or during use.